The hydrogenation of acetylene in industrial scale is typically used for purification of ethylene produced by ethane stream cracking from small amounts (0.5-0.9 mol-%) of acetylene.
U.S. Pat. No. 4,585,897 discloses a process for hydration and condensation of acetylene in a crude acetylene stream containing water in the presence of a zirconia-alumina catalyst containing water.
U.S. Pat. No. 2,723,299 discloses a process for preparing styrene and benzene by heating a mixture of acetylene and monovinyl acetylene to a specific temperature under a specific pressure in the presence of a nickel-based catalyst.
U.S. Pat. No. 4,009,219 discloses a process of producing benzene wherein lithium carbide which has been produced is hydrolysed to produce acetylene which is subsequently cyclysized to produce benzene.
Further, U.S. Pat. No. 4,982,032 discloses a process for the conversion of a wet acetylene-containing stream to a product rich in the aromatics benzene, toluene and xylene, wherein the acetylene-containing stream is contacted with a promoted catalyst composition comprising a minor amount of zinc ion incorporated in a major amount of a borosilicate molecular sieve composited in an inorganic matrix.
U.S. Pat. No. 4,227,025 discloses a process for the effective removal of acetylene from a first gas feed which comprises feeding said gas together with hydrogen at an acetylene removal temperature in contact with a noble metal hydrogenation catalyst.
U.S. Pat. No. 4,227,025 discloses in detail the hydrogenation of acetylene in ethylene-containing mixture for purification of ethylene from about 2.200 ppm of acetylene in the presence of a catalyst of Pd supported on Al2O3.
Further, U.S. Pat. No. 4,128,595 discloses a process for the selective hydrogenation of acetylenic compounds in the liquid phase which comprises contacting hydrogen and a gaseous hydrocarbon stream containing acetylene with a supported catalyst comprising a group VIII metal under hydrogenation conditions.
Up to now, Pd based industrial catalysts on a support can operate only at low concentrations of acetylene (0.5-0.9 mol-%), and even at these concentrations the catalyst deactivates because of the formation of heavy hydrocarbons, which are called green oil. Therefore, for such processes deep hydrogenation reactions are characteristic, which lead to the loss of ethylene.
The typical gas compositions from methane pyrolysis step contain 8-10 wt.-% acetylene, and the existing catalyst systems cannot work in the presence of this amount of acetylene due to the very fast deactivation of the catalyst by formation of coke fragments. Therefore, traditional catalytic acetylene hydrogenation has the following disadvantages:                Acetylene hydrogenation to ethylene is used only for purification of ethylene from small amounts of acetylene. These methods cannot be used for hydrogenation of high amounts of acetylene for production of ethylene.        Traditional processes of gas phase purification of ethylene from acetylene hydrogenation lead to the loss of some ethylene because of low selectivity of these catalysts.        During traditional gas phase acetylene hydrogenation on Pd-based catalysts the formation of green oil on the surface of catalysts takes place leading to the deactivation of the catalyst.        The traditional gas phase hydrogenation processes are limited with regard to the ratio of hydrogen to acetylene which has to be controlled specifically for keeping a high selectivity of ethylene.        The traditional gas phase hydrogenation processes require the specific control of the reaction temperature, run away of the temperature leads to a sharp decrease of selectivity.        Further, traditional gas phase hydrogenation processes require the specific control of the amount of carbon monoxide in the feed; without the addition of carbon monoxide the selectivity of ethylene is low, whereas at high concentrations of carbon monoxide, for example more than about 1.200 ppm, the conversion of acetylene decreases almost to zero due to the strong adsorption of carbon monoxide.        
Due to these problems, it is very difficult to realize the hydrogenation of acetylene at high concentrations for production of ethylene from acetylene.
U.S. Pat. No. 5,118,893 discloses a catalytic conversion of acetylene in the presence of nickel or cobalt-containing zeolite catalyst with the addition of hydrogen to the acetylene feed. It was observed that acetylene conversion in the presence of zeolite-containing catalyst leads to the rapid deactivation of catalyst due to very fast polymerization of acetylene on the surface of the catalyst.
It was reported that with the increase of acetylene concentration in the mixture deactivation of catalyst proceeds very fast.